This Core functions to provide a central unit that coordinates and carries out all administrative functions of the Center, provides clinical expertise and service to the Center by identifying and characterizing appropriate human subjects, and works closely with the Center investigators to plan protocols, store and retrieve data, and carry our data analyses. The Core facilities are provided by the Virginia Commonwealth University School of Dentistry via its Clinical Research Center for Periodontal Diseases, and include office space, laboratory space, and a research clinic. The Clinical Core comprises a group of six clinical investigators and support staff. In addition to their role in planning clinical research protocols, the investigators participate in the examination, characterization and treatment of clinical subjects who participate in the Center projects. Investigators are supported by staff that include a dental assistant and a field worker who contact and appoint subjects and assist with data collection, data entry, and routine clinical duties. The clinical core thus provides the clinical data and derived samples required to carry out the research goals of all projects. The Biostatistics Core provides professional data base management and biostatistical services to all projects. The staff includes two biostatisticians experienced in analysis of data from studies of periodontal diseases and a data base manager who developed the current data storage system and retrieves data for use of investigators in all projects.